Spano: Raised hackles by suggesting his critics were racist.Robert Kalfus

Why did Westchester voters throw out incumbent County Executive Andy Spano in favor of Republican challenger Rob Astorino by an impressive 58-42 margin?

Taxes no doubt ranked high as an issue. But it didn’t help that residents felt strong-armed into a controversial lawsuit settlement on low-income housing that cuts deeply into the county’s tradition of home rule on development issues — or that Spano reacted to voter discontent by suggesting that critics of his housing plans were racist.

Announced in August, the settlement calls for the county over seven years to override local zoning and other rules to force the construction of at least 750 low-income housing units, most to be located in relatively affluent towns. The intent is to increase the number of poorer minorities living in these areas.

A federal judge had sided with plaintiffs’ complaints that the county had accepted federal funds but not lived up to its talk of combating purported “segregation” based on income. (In fact, affluent blacks and other minorities have long been welcome in many of these communities; as the Manhattan Institute’s Howard Husock points out, blacks are at most slightly underrepresented in towns like Scarsdale, Harrison and Pound Ridge compared with their overall presence in those towns’ typical income brackets.)

The Obama administration took credit for arm-twisting the county into going along: “This is historic, because we are going to hold people’s feet to the fire,” said Housing and Urban Development Deputy Secretary Ron Sims, who added: “It’s time to remove Zip codes as a factor in the quality of life in America.”

Read that last line again. To remove Zip codes “as a factor in the quality of life” in a nation — so that 10455 (the South Bronx) and 91731 (El Monte, Calif.) have exactly the same implications for quality of life as 10021 (the Upper East Side) and 90210 (Beverly Hills) — would require extreme ventures into social engineering.

Even Scandinavian social democracy hasn’t managed it: Cities like Stockholm and Copenhagen include both chic, desirable neighborhoods and neighborhoods that are neither.

What measures might be called for to remove Zip code as a quality-of-life factor differentiating crime-plagued Mount Vernon from calm Mamaroneck? Basically, the county agreed to force villages and towns to change zoning laws that implicitly discourage “affordable housing,” such as relatively cheap, dense development — and perhaps to appropriate vacant property for the purpose.

Not surprisingly, Westchesterites reacted with alarm. Aside from the abridgment of home rule, a requirement to accept dense development would probably bring new costs (the introduction of water and sewer systems, school expansion), which would be unlikely to be offset by property-tax collections on the new developments. Planning to use a vacant parcel for new softball fields, or to preserve it as open space? Sorry: Using town property for purposes that residents favor could put the supervisors in violation of the settlement.

Many voters wondered whether Spano, a Democrat, had in fact fought hard against going along — or had caved too readily to what both sides agreed were unprecedented demands (including $10 million for the plaintiffs and their lawyers).

After all, the deal offered Spano certain political advantages, including relatively favorable press in both The New York Times and the local, reliably liberal Journal News, both of which applauded the settlement on their editorial pages.

Spano insisted that the county was yielding against its will. Yet he also used the quiet weeks leading up to Labor Day to steamroll the plan through a compliant board of county legislators. Astorino called for a slowdown to examine whether the county had really exhausted its options. Spano replied by playing the race card, saying delay would “make us a symbol of racism.”

The locals don’t like being talked to that way: Westchester is known for racial liberalism from way back, and voted for Barack Obama by a comfortable margin. Now Spano, despite a well-financed campaign and all the advantages of incumbency and union backing, is packing for his departure.

Astorino, just recently written off as a long shot, will be moving into his office. And officials of other local governments have a new reason to fight, not just go along meekly, when the social engineers and lawyers come knocking at their door.

Walter Olson, a Manhattan In stitute senior fellow, posts as Mid Westchester on Twitter, as well as under his own name. From city- journal.org.